Adjustment for optical systems



Sept. 27, 1938. A p s 2131280 ADJUSTMENT FOR OPTICAL SYSTEMS Filed Feb. 15, 1936 TTE. E

INVENTOR. PA UI HAAS BY Wf/ ATTORNEY n narrow line of light upon the sound record. portions engaged thereby to rmly lock the ad- Patented Sept. 27, 1938 UNITED STATES PATENT OFFICE.

2,131,2so i ADJUSTMENT FOR OPTICAL SYSTEMS Paul Haas, Glendale, Calif., assignor to United Research Corporation, Burbank, Calif., a corporation of Delaware Application February 15, 1936, Serial No. 64,106 3 Claims. (oi. 88-24) This invention relates to sound recording and of clamp or lock screws through the projections reproduoing through the use of a photographic are provided for fie'xing the fiexible projections, sound record and more particularly to the adthus producing sufcient friction between the justment of the optical system for focusing a threads of the adjusting screws and the threaded In both recording and reproducing sound from justing screws in any desired position. The locka photographic sound film a beam of light in the ing or clamping screws are so set that very little form of a very fine line is focused upon the film movement thereof is required to accomplish the at the sound track with its length extending looking of the adjusting screws, the looking optransversely of the travel of the film. In recorderation thereby not disturbing the adjustment. 10 ing, this line of light is made to expose the photo- For further details of the invention, reference sensitive film and in this case the intensity of may be had to the accompanying drawing, the line of light may be made to vary in accordwherein: ance with the amplitude of the sound being re- Fig. 1 is a perspective view, partly in section,

corded, as in the variable density type, or the of a sound reproducing device embodying my inir length of the line of light, measured transversely vention. of the film travel, may be made to vary in ac- Fig. 2 is a sectional View taken along the line cordance with the amplitude of the sound, as in 2-2 or Fig. 1 and showing the azimuth adjustthe variable area type of recording. In reproment of the lens tube.

duction this line of light is generally kept at a Fig. 3 is a front View of the lens tube and its 20 constant intensity and constant length and is support and is taken in the direction of the arcnanged either in intensity or in length by the row 3 of Fig. 2. sound record on the' film. However, in practi- Referring now to Fig. 1, an exciter lamp 3 havcally all cases, this line of light is produced by ing a rectilinear filament 4 displaced in a horipassing a beam of light through a very fine slit zontal position projects a beam of light through 25 or narrow aperture, lenses being employed before a lens tube generally indicated at 5, from Whence and/or after the slit to focus the line of light it is focused upon the sound track portion 6 of upon the film. a motion picture film 'l which is adapted to be Since the line of light should be of the order moved in a Vertical direction at a constant speed of .001" or lessinwidth and approximately .084" by any well known sound film driving means 30 in length, it is not only necessary that it be ac- (not shown). A light sensitive device such as a curately focused but also properly oriented with caesiun or potassium cell 8 is provided behind respect to the position of the film or sound track. the film 'I so as to receive the beam of light modu- That is, the adjustment of the azimuth of the lated by the sound track portion '6 and to genlight line must be under vernier control together erate an electric current varying directly in ac- 35 with a looking means which does not disturb the cordance with' the modulated beam of light. The adjustment. The above applies to all recording currents generated by cell 8 are passed through and reproducing of sound of which the variable leads 9 into an amplifier diagrammatically indiarea and variable density types are the most notacated at o and thence into a loud speaker ll.

' ble ples. The sound track portion 6 of film 'I is 'shown as 40 The present invention is directed to the adbeing of the variable density type wherein the justment' of the slit forming member about an sound is recorded as vertically spaced horizontal axis coaxial with the beam of light passing therestriations H whose opacity varies with the inthrough, and has for an object to adjust and lock stantaneous Volume of the sound recorded and the slit forming member in a desired position. whose center distances are determined by the 45 This iS accomplished y rotatably ppo frequency. However, the track 8 may be of the the slit member in asuppor Preferably the slit variable area type wherein the Volume of the member is incorporated in a lens tube which in sound d t r i d by the amount of opaeity turn is rotatably held in the support. A lug atacross the width of the track.

tached to the tube and movable with respect to In employing either a variable area or variable 50 projections from the support is adapted to be density type of sound track, the light from the ed and moved by adust ng screws threadexciter lamp 3 is focused upon the film 'I in the ably held by the projections. The projections form of an extremely narrow horizontal line of may consist of separated pairs, one projection of light. This is accomplished by means of a slit each pair being semi-fiexible. Means in the form 12 formed by a slit member !6 within the tube 55 5 which co-acts with a condenser lens !3 and a pair of objective lenses I@ and !5. Especially in the case of variable density records, it is absolutely essential that the line or slit of light falling upon the sound track portion of the film be parallel to the horizontal striations upon the sound track. The importance of this will be realized when considering the fact that at higher frequencies, say 9,000 cycles per second, the width of a single striation which corresponds to one half wavelength, becomes on the order of about .001 inch or less.

Referring now to Figs. 2 and 3, I will describe the means for adjusting the line of light focused upon the film and which forms the main embodiment of my invention. A lens support or holder !8 is provided which may be suitably secured upon the wall or casing (not shown) of the sound reproducing device. Tube 5 is mounted in a split sleeve arrangement !9 provided in the front of support l8. Bosses 2l and 22, are integrally formed upon the support !8 on either side of a slit 20. Clamp screw 23 passing through boss 2| and threadably secured in the rear boss 22 is provided to clamp the lens tube 5 in any position after adjustment.

Tube 5 has a lug 25 secured to the circumference thereof as by screws 26 and is adapted to be engaged on the opposite sides thereof by a pair of set screws 21 and 28. screws 21 and 28 are threadably Secured in pairs of projections 29 and 30 respectively, extending from the main body of the support !8. Each pair of projections comprises a relatively stifi projection 3| and a more or less flexible projection 32, both of which are preferably formed integral with the support !8. However, it is obvious that one or both of the projections 3| and 32 may be formedseparately and Secured as by means of suitable screws to the side of support !8. Clamp or lock screws 34 pass through the end of each projection 3| and are threadably Secured within the inner flexible projection 32.' Although the fiexible projections 32 are shown as being interposed between the rigid projection 3l and the lug 25, it is obvious that these projections may be placed on the outside of the rigid projections 3l.

In adjusting the tube 5 so that the line of light imaged by the slit I2 falls upon the sound track 6 exactly parallel to the horizontal striations, the clamp screws 34 are tightened suffciently to put a considerable friction upon the threads of either of the screws 21 and 28 by means of the fiexing of the projections 32. This pressure, however, is not sogreat that it will prevent turning of either of set screws 21 and 28. When the azimutnof tube 5 is accurately located the clamp screws are required to be rotated only slightly to frictionally lock both the screws 21 and 28 in their final adjusted position.

There is no tendency therefore to change the relative positions of the screws 21 and 28 and disturb their adjustment.

Either after, during, or preferably before the azimuth adjustment, the tube 5 is focused by moving it to or from the film until a clear and sharp image of the slit l2 'is formed thereon. After the lens has been adjusted for both focus and azimuth alignment the clamp screw 23 may be tightened without affecting either adjustment.

Having thus described the invention, what is claimed as new and desired to secure by Letters Patent, is:

1. In an optical system for a sound reproducing apparatus, a lens tube, a support for said tube, a slit forming member in said tube, and an azimuth adjusting means for said tube comprising, a lug on the circumference of said tube, a pair of substantially rigid projections on said support, screws threadably mounted in said projections for engaging opposite sides of said lug and adapted to adjust the azmuth of said tube, the ends of said screws Contacting said lug being substantially flat fiexible projections on said support adjacent each of said first mentioned projections, said screws being threaded through said fiexible projections, and clamp screws passing through said rigid projections and threaded into said flexible projections.

2. In a sound reproducing apparatus consisting of a lens tube for focusing a beam of light upon'a photographic sound record moving across the axis of said tube, a slit in said member for converging said beam into a narrow line of light, a support for said tube, and means for adjusti ing the azimuth of said tube comprising, a lug on the circumierence of said tube, a pair of projections on said support adjacent one side of said lug, a second pair of projections adjacent the opposite side of said lug, a set screw threaded through each pair of projections and adapted to engage each of said opposite sides of said lug, the contact ends of said set screws being substantially fiat, and means on each pair of said projections for fiexing one projection relative to the other projection, said means comprsing a screwthreaded into one projection of each pair and Contacting the other projection of each pair.

3. In a sound reproducing apparatus consisting of a lens tube for focusing a beam of light upon a photographic sound record moving across the axis of said tube, a slit in said member for converging said beam into a narrow line of light, a support for said tube, and means for adjusting the azimuth of said tube comprsing, a lug on the circumference of said tube, a pair of projections on said support adjacent one side of said lug, a second pair of projections adjacent the opposite side of said lug, one projection of each of said pairs being relatively fiexible, a set screw threaded through each of said pairs and having a substantially flat contact surface with said lug and means on each pair of said projections for fiexing each of said flexible projections to lock said set screws in position.

PAUL HAAS. 

